Lithium calcium hexafluoroaluminate(LiCAF) crystals are widely used as vacuum ultraviolet(VUV) and ultraviolet(UV) laser host media. It has excellent transmission characteristics down to the vacuum ultraviolet (VUV) region. The transmission edge of LiCAF was measured experimentally to be 112nm. In particular, LiCAF has a transmittance of over 95% at 157nm, which corresponds to the wavelength of an F2 laser. It was also shown that LiCAF becomes virtually non-birefringent around 152nm, thereby making it an attractive optical window material for VUV laser sources LiCAF(LiCaAIF6) are excellent laser materials with high energy storage and high slope efficiency, also ideal working material under conditions of ultra short pulse and ultra high power.
Parameter
Orientation Tolerance | 5ˊ |
Parallelism | <10〞 |
Perpendicularity | 5ˊ |
Chamfer | 0.1mm@45° |
Surface Quality | 10/5 or better |
Wavefront Distortion | λ/8 @632.8 nm |
Surface Flatness | λ/10 @632.8 nm |
Clear Aperture | >95% |
Diameter Tolerance | +0/-0.05mm |
Length Tolerance | ±0.1mm |
Coatings | As per requirement |
Damage Threshold | over 15J/cm2 TEM00, 10ns, 10Hz |
Dopant Concentration Tolerance | 0.10% |
Lattice | HexagonaL |
Space Group | P31C |
Lattice Constants | a=5.006, c=9.636Å |
Density (g/cm3) | 2.94 |
Melting Point | 825°C |
Thermal Conductivity(W·m-1·K-1) | 5.14(∥a), 4.58(∥c) |
Thermal Expansion(10-6·K-1) | 3.6(∥a), 22(∥c) |
Specific Heat(J·g-1·K-1) | 0.935 |
Fracture Toughness(MPa·m1/2) | 0.18~0.37 |
Band Gap(eV)@LDA | 8.02(indirect) |
Young’s Modulus(GPa) | 105.32(∥a), 94.89(∥c) |
Bulk Modulus(GPa) | 108.01 |
Dielectric Constant | 1.27 |
Absorption Edge | 112nm |
Refractive Index | no=1.3826, ne=1.3826@632,8nm |
Thermal-optical Coefficient(10-6/°C) | -7.3(no), -4.9(ne) |
Wavelength(nm) | no | ne |
632.8 | 1.3826 | 1.3826 |
546.1 | 1.384 | 1.384 |
435.8 | 1.3862 | 1.3862 |
253.7 | 1.4061 | 1.4073 |
- Large band gaps and low phonon energies
- Optical transmission and low thermal lensing distortion
- Absorption edge is 112nm
- Small non-linear refractive indices
- Transparency, tolerance to laser-induced damage
- Lase host media
- Lens in VUV photolithography
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